Sea Sled madness. It’s in my brain.

Great, @fallguy ! Don't know why that's not coming up in searches, but those units are beasts, at a reasonable cost.

 

John-the jpl 4500 is the one I used in black .. 6" setback adds to my l/b ratio as well

 

I was thinking the same unit, in base metal.

 

The black is thicker anodizing I was told....give them a call. I think there are a couple ways to win here. You can also run long legs if you want AND you get to tweak the cav plate height some.

Can you ask Ad Hoc to review your stringers on the back? I am nervous they are lacking. I would sort of assume two knees per engine to transfer loads to the hull. The sole is an imperfect ******* to expect load transfer because it is not tabbed to the hull bottom.

All the best.

 

I am just a bit uncertain about where powerheads go and the single stringer for twins on the back is bothering me a bit. I sort of was expecting two sets of stringers where engines go.. one could be short and only to a splashwell BH...but all a gut is all..

 

I see what you're referring to @fallguy . The stringer? Terminology... do you mean the member that runs across the transom that the sole bonds down to? Or the low longitudinal bulkheads that go from the transom forward to BH#6? Everything will be epoxied and tabbed and bolted or screwed at the end. The members from p to s on the bulkhead aren't all there yet, the middle one is only dry fitted. Just sizing bits.

The sole will be tabbed to the primary bulkhead (#6), the transom, hull sides, and the tops of the 1" - 25mm longitudinals. All those components are solid load paths from the transom to the rest of the hull. Although your intuition may well be right, and that may not be enough. I frankly lack the math to determine by first principles. Lost it with my hair in the decades since I was taking vector mechanics and analytic geometry. Although I did trade them all in on a nice pot belly, and several hundred scars, so that's ok. Let's call it even.

 

I am just not sure where the powerheads reside, but I would have wanted two stringers in front of each engine for a 10 foot beam. The stringers are in gold

 

Ok, I see what you mean by stringers. The components highlighted in gold are longitudinal bulkheads. The outboards are probably going to be centered on the port and starboard compartments so the bulkheads you've highlighted in gold will act in concert with the sides of the hull, forming the pairs you suggest.

 

Is the outboard between those 2 gold long.ts?

 

No, he is planning twin ob just outside/outboard of my purple blob.

 

Somewhere here, blue area..but there is only really one stringer/long t..

 

AAaaahh.. in that case he really needs an additional load path:



A long.t bkt/knee like shown in black....between the fixings of the O/B, and taken as high up the transom as possible.. and then going fwd, to a transverse to finish.

 

Check my math, but I mean to add a fully bonded, completely structural sole that runs from the transom to the primary bulkhead, down onto those 2 25mm plywood longitudinal bulkheads, and out to the hull sides.

 

For me, the main problem with the sole is it can only be tabbed on top and so the hull doesn't get the loads transferred as well, but AH is the wiser owl.

 

Well, if this was foam and glass, that would be a greater concern. Since it's very hefty wood, I can build thick ledgers and lag screw them at the transom and the bulkhead, then screw down through the plywood into them. It's still not as good as upper and lower fillets, but the withdrawal force per screw is roughly 300# or 135kg. After the ledger is bedded in thickened epoxy, and has 6 screws in it, then the epoxy fill is placed, then upper fillet and tabs, the final assembly has a comfortable safely margin... I think. I left engineering school to become, ironically, a combat engineer. It clarifies my thinking when the actual smart people challenge decisions, and I have to defend them with math.